
We’ve all seen the Bond films, The Day of the Jackal, or even Slow Horses. Most of us have strolled past that historic building in Vauxhallsneaking a curious glance and wondering what really goes on behind those walls – I know I have.
Now, for the first time ever, Londoners are being given a rare glimpse into the secretive world of MI5 and the extraordinary stories behind the UK’s most enigmatic security agency.
No more sneaky glances required as for the first time ever and made possible through an unprecedented partnership between the Security Service and The National Archives – this major new exhibition called MI5: Official Secrets will showcase the MI5’s history to the public and for FREE. Yep yep, you know we love all free things.
From a passport belonging to one of the Cambridge spies to a letter about the Queen’s response to the news of a Soviet agent in Buckingham Palace – there’s plenty of never-seen-before MI5 artefacts and declassified documents on display.
One of the exhibition’s more unusual centrepieces is a 110-year-old lemon – once a key piece of evidence in the case against German spy Karl Muller. In 1915, Muller was executed by firing squad at the Tower of London after being caught using lemon juice as invisible ink to pass on British troop movements. When investigators arrested him, they found the lemon tucked inside his overcoat. Heated with an iron, the letters he wrote revealed their hidden messages.
Also on display are some remarkable artefacts from MI5’s archives: the agency’s first covert camera, a key to the Communist Party of Great Britain’s Westminster HQ, and a Provisional IRA mortar bomb.
So step inside the shadowy world of espionage and shifting security threats at this landmark exhibition at The National Archivesas told through original case files, declassified photographs, and real spycraft tools spanning MI5’s 115-year history.
From wartime counter-espionage and double agents to Cold War betrayals and the modern fight against terrorism, this landmark exhibition offers an unprecedented look behind the curtain of Britain’s most secretive agency.
The exhibition is open from now until September 28, 2025. You can find more information here.